The present invention relates generally to devices and methods for inspecting tooth surfaces, and in particular to such devices and methods involving the detection of differential fluorescence emissions from abnormal and healthy tooth surfaces.
As further background, various devices and methods have been proposed that involve using fluorescence emissions to detect caries or other abnormal conditions. For example, U.S. Pat. No. 3,711,700 relates to a disclosing light for inspecting tooth surfaces. The disclosing light is designed for use in conjunction with a fluorescent dye such as sodium fluorescein. The disclosing light includes a light source and a dichroic reflector behind the light source to reflect blue light forward and the remainder backward. A second dichroic filter is positioned in front of the light source and transmits blue light and reflects back infrared radiation. A mirror reflects yellow light to the observer and transmits other wavelengths.
U.S. Pat. No. 4,266,535 discloses a diagnostic lamp for use in conjunction with a fluorescent dye to inspect tooth surfaces. The lamp includes an incandescent bulb light source used in conjunction with a lens to supply a divergent beam of rays. A blue filter with an applied dichroic filter is used to filter the rays, which are made to impinge upon the fluorescent dye. The resulting fluorescence can be viewed in a folding, adjustable mirror. U.S. Pat. No. 5,957,687 discloses another diagnostic unit including a filtered light source and a mirror contained in a housing. Filtered light is concentrated in the blue frequency range and causes fluorescent dye to fluoresce. This can then be viewed in the mirror.
U.S. Pat. No. 4,290,433 discloses a method and device for detecting caries in human teeth using luminescence. The luminescence from teeth is measured at two predetermined wavelengths, one of which is about the same for caries-containing and non-caries-containing surfaces, and another where the luminescence is higher for caries-containing surfaces. A signal is generated corresponding to the difference in the intensities at the two measured wavelengths. A baseline measurement is taken at a non-decayed region, and the probe is then directed to other regions to assess the presence or absence of caries.
U.S. Pat. No. 4,515,476 describes a device for the ocular determination of discrepancies in the luminescence capacity of tooth surfaces. The disclosed device includes an argon laser for generating visible light in a predetermined wavelength range that causes luminescence from tooth surfaces. An absorption filter is used to eliminate reflections and luminescence within the predetermined wavelength range of the laser light. In this fashion, unsound tooth surface areas such as caries can be viewed as dark areas.
U.S. Pat. No. 5,894,620 discloses an electric toothbrush with means for locating dental plaque. The electric toothbrush includes an optical fiber for transmitting excitation radiation to tooth surfaces, and an optical fiber(s) for receiving a return luminescence or fluorescence signal. The return signal is then processed to activate a light or audible signal indicative of the presence of plaque.
In light of this background, there remain needs for improved, convenient devices and methods for tooth surface inspection to detect caries and other surface abnormalities. The present invention is addressed to these needs.